Production of hydrocarbons

Abstract

A process for producing hydrocarbons involves allowing reactants forming part of a reaction medium in a reaction zone, to react at reaction conditions so as to form primary hydrocarbon products. Water is formed as a by-product. The by-product water, on formation under the reaction conditions, is allowed to permeate through a porous membrane, thereby to be separated from the reaction medium.

What is claimed is:  
     
       1. A process for producing hydrocarbons, which process comprises: 
       allowing reactants forming part of a reaction medium in a reaction zone, to react at reaction conditions so as to form primary hydrocarbon products, with water being formed as a by-product; and  
       allowing by-product water, on formation thereof under the reaction conditions, to permeate through a membrane that selectively removes water from the reaction medium, thereby to be separated from the reaction medium.  
     
     
       2. A process according to  claim 1 , wherein the reactants are in gaseous form and comprise carbon monoxide and hydrogen, with a particulate Fischer-Tropsch catalyst also forming part of the reaction medium, and with the reaction conditions being such that the carbon monoxide and hydrogen react in the presence of the Fischer-Tropsch catalyst, to produce, as the primary hydrocarbon products, liquid Fischer-Tropsch derived hydrocarbon product(s) and/or gaseous Fischer-Tropsch derived product(s), in accordance with a simplified Fischer-Tropsch reaction equation (1): 
       
         
           CO+(1+x)H 2 →CH 2x +H 2 O   (1).  
         
       
     
     
       3. A process according to  claim 2 , wherein the reaction zone is provided by a slurry bed reactor, the slurry bed of which comprises liquid hydrocarbon products, gaseous hydrocarbon products, water, gaseous reactants, and catalyst particles, with the membrane thus being located within the slurry bed, and with the reaction medium also comprising liquid hydrocarbon products, gaseous hydrocarbon products, water, gaseous reactants and catalyst particles. 
     
     
       4. A process according to  claim 2 , wherein the reaction zone is provided by a fluidized bed reactor, the fluidized bed of which comprises gaseous hydrocarbon products, gaseous reactants, water, and catalyst particles, with the membrane thus being located within the fluidized bed, and with the reaction medium also comprising gaseous hydrocarbon products, water, gaseous reactants and catalyst particles. 
     
     
       5. A process according to  claim 1 , wherein the membrane is supported by a water-permeable support such that the membrane has a water inlet side and a water outlet side, with the by-product water thus entering the membrane through its water inlet side, permeating through the membrane, and exiting the membrane through its water outlet side, and with the support and the membrane thus forming a water separation device. 
     
     
       6. A process according to  claim 5 , which includes passing an inert sweep gas along the support in proximity to the water outlet side of the membrane, to entrain water which permeates through the membrane, thereby to provide a driving force for water permeation through the membrane. 
     
     
       7. A process according to  claim 6 , wherein the support is of tubular form with the membrane being provided on the inner or the outer surface of the tubular support, and with the sweep gas passing through the inside of the membrane. 
     
     
       8. A process according to  claim 7 , wherein the sweep gas enters the reaction zone through a conduit connected to the inside of the tubular support at or near one end thereof, passes through the support, and exits the reaction zone through another conduit leading from the support at or near another end thereof, out of the reaction zone. 
     
     
       9. A process according to  claim 5 , wherein the membrane is of porous zeolitic material selected from mordenite, ZSM-5, zeolite A, and chabazite. 
     
     
       10. A process according to  claim 5 , wherein the water-permeable support is of porous stainless steel.